Cleaning blade having an elastic body of segmented hardnesses, and image forming apparatus and process cartridge including the cleaning blade

Abstract

A cleaning blade cleaning the surface of an object includes a rigid holder; and a strip-shaped elastic body fixed on the holder, including a tip ridgeline contacting the surface of the object. The elastic body has a length (L) projecting from the holder not less than 4 mm, a Martens hardness of from 1.0 to 10.0 N/mm 2 from the tip ridgeline to the middle (L/2) thereof, and a Martens hardness of from 0.3 to 0.8 N/mm 2 from the middle (L/2) thereof.

What is claimed is: 
     
       1. A cleaning blade for cleaning a surface of an object, comprising:
 a rigid holder; and 
 a strip-shaped elastic body fixed to a side of the holder, comprising a tip ridgeline configured to contact the surface of the object, 
 wherein the elastic body includes an extension portion that extends beyond the side of the holder in a direction parallel to the side of the holder by a length (L) of not less than 4 mm, 
 wherein a Martens hardness is in a range of from 1.0 to 10.0 N/mm 2  at an area from the tip ridgeline to the middle (L/2) of the extension portion on a surface of the blade, and 
 wherein a Martens hardness is in a range of from 0.3 to 0.8 N/mm 2  at an area from the middle (L/2) of the extension portion on the surface of the blade to a point where the elastic body first extends beyond the side of the holder in a direction parallel to the side of the holder. 
 
     
     
       2. The cleaning blade of  claim 1 , wherein the elastic body has a Martens hardness of from 1.0 to 5.0 N/mm 2  from the tip ridgeline to the middle (L/2) thereof. 
     
     
       3. The cleaning blade of  claim 1 , wherein the elastic body has a maximum value of the Martens hardness within 500 μm from the tip ridgeline. 
     
     
       4. The cleaning blade of  claim 1 , wherein the elastic body comprises a part where a polyurethane rubber and an acrylic cured resin are mixed. 
     
     
       5. An image foil ling apparatus, comprising:
 an image bearer; 
 a cleaning member configured to contact the surface of the image bearer to remove an unnecessary material adhering thereto; and 
 a transfer member configured to transfer an image on the image bearer onto a recording medium, 
 wherein the cleaning member is the cleaning blade according to  claim 1 . 
 
     
     
       6. A process cartridge detachable from image forming apparatus, comprising:
 an image bearer; and 
 a cleaning member configured to contact the surface of the image bearer to remove an unnecessary material adhering thereto, 
 wherein the cleaning member is the cleaning blade according to  claim 1 . 
 
     
     
       7. A cleaning blade cleaning a surface of an object, comprising:
 a rigid holder; and 
 a strip-shaped elastic body fixed to a side of the holder, comprising a tip ridgeline configured to contact the surface of the object, 
 wherein the elastic body includes an extension portion that extends beyond the side of the holder in a direction parallel to the side of the holder by a length (L) of not less than 4 mm, 
 wherein a Martens hardness is in a range of from 1.0 to 10.0 N/mm 2  from the tip ridgeline to the middle (L/2) of the extension portion, and 
 wherein a Martens hardness is in a range of from 0.3 to 0.8 N/mm 2  from the middle (L/2) of the extension portion to a point where the elastic body first extends beyond the side of the holder in a direction parallel to the side of the holder, 
 wherein the elastic body comprises a part where a polyurethane rubber and an acrylic cured resin are mixed, and 
 wherein the acrylic cured resin comprises a fluorine-based acrylic monomer.